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Biomedical subjects

B B Gorzalka

Publications and source records attributed to B B Gorzalka.

At least 55 records · Page 3Linked to original sources
PubMed1990

Hormone-dependent aggression in male rats is proportional to serum testosterone concentration but sexual behavior is not.

Male hooded rats were castrated and implanted with Silastic capsules (1.57 mm i.d.; 3.18 mm o.d.) having a testosterone-filled space 0, 7, 22, 60, or 90 mm long. All animals were returned to their original group cages for a three-week period to allow hormone concentrations and behavioral tendencies to stabilize. Each male was then housed with an intact female in a large cage. Aggression by the male toward an unfamiliar male was tested at weekly intervals for three weeks. Sexual behavior with an estrogen/progesterone-primed ovariectomized female was tested on each of the subsequent two weeks. Serum testosterone was measured during the following week. The frequency of aggression was correlated with serum testosterone concentration up to the normal level and did not increase with higher serum testosterone concentrations. In contrast, sexual behavior was virtually absent in animals with no testosterone replacement and normal in all other groups. These results demonstrate a clear dissociation in the dependence of hormone-dependent aggression and sexual behavior on serum testosterone concentration. In a male cohabiting with a female, sexual experience activates hormone-dependent aggression toward an unfamiliar male but the level of aggression that develops depends on the serum testosterone concentration in the resident male.

Aggression↗
PubMed1990

Relation of spontaneous wet dog shakes and copulatory behavior in male rats.

Pharmacological manipulation of 5-HT2 activity has yielded equivocal effects on male rat sexual behavior. Both facilitation and inhibition of copulation have been reported following treatment with 5-HT2 antagonists. "Wet dog shake" (WDS), a component of the Serotonin Behavioral Syndrome, is largely mediated by 5-HT2 receptors. The present series of experiments were aimed at determining whether WDS might yield a spontaneous behavioral measure of 5-HT2 activity that converges on the pharmacological data. In Experiment 1, spontaneous WDS was recorded in 58 male rats paired with receptive females. Normal copulators (Studs) exhibited significantly less WDS than did noncopulators (Duds). In Experiment 2, the males were additionally paired with males and nonreceptive females. In these situations, WDS did not discriminate Duds from Studs, but Studs scores differed from each other across the three different partner conditions. Lastly, in Experiment 3, treatment with the selective 5-HT2 agonist DOI potently inhibited copulatory responses and increased WDS. Overall, the data from the three experiments suggest that 5-HT2 activity mediates an inhibition of male rat sexual behavior.

Amphetamines↗
PubMed1990

The enhancing effects of anxiety on arousal in sexually dysfunctional and functional women.

Effects of anxiety on sexual arousal were examined to determine if sexually dysfunctional and functional women exhibit different patterns of physiological and subjective response. Subjects viewed 2 videotape conditions: an anxiety-evoking and neutral-control preexposure stimulus, each paired with a sexual arousal-evoking stimulus. Anxiety preexposure enhanced the rate and magnitude of genital arousal for both dysfunctional and functional subjects in relation to the neutral condition. Despite increased genital responses, both groups reported less subjective sexual arousal after anxiety preexposure. Functional subjects exhibited greater physiological but not subjective arousal than dysfunctional subjects in both conditions. Results are discussed in terms of desynchronous patterns of sexual response, mechanisms by which sympathetic activation enhances sexual arousal, and implications for treatment of sexual dysfunction in women.

Adult↗
PubMed1988

Stimulation of beta-adrenoceptors inhibits lordosis behavior in the female rat.

Existing reports on the effects of beta-adrenergic antagonists on lordosis behavior appear contradictory, with (+/-) propranolol being reported to inhibit, and (+/-) pindolol to facilitate this behavior. In the present study, both the (-) and (+) optical isomers of propranolol were effective in inhibiting lordosis behavior in ovariectomized rats treated with estrogen and progesterone. This finding suggests that the lordosis-inhibiting effects of propranolol were not due to blockade of beta-adrenergic activity, but rather to the membrane stabilizing effect of the drug. An observed inhibition of lordosis following the peripheral administration of the local anesthetic lidocaine is consistent with this possibility. (+/-) Propranolol had no effect 30 min after peripheral administration in estrogen-treated, ovariectomized rats with low baseline levels of lordosis behavior. (+/-) and (-) pindolol, but not (+) pindolol also inhibited lordosis 30 min after administration. However, in addition to its antagonist effects, pindolol acts as a partial agonist in some tissues. Centrally active doses of the pure beta-antagonist (+/-) metoprolol produced no inhibitory effects. Indeed, metoprolol reversed the inhibitory effect of the beta-agonist (+/-) salbutamol. This suggests that the lordosis-inhibiting effects of pindolol were due to its partial agonist effects. Taken together, the present data indicate that activity at central beta-adrenoceptors inhibits rather than facilitates lordosis behavior.

Animals↗
PubMed1988

Effect of novel and familiar mating partners on the duration of sexual receptivity in the female hamster.

The lordosis duration of the female golden hamster (Mesocricetus auratus) in response to novel and familiar mating partners was examined. In Experiment 1, females mated to the point of sexual satiation with one male hamster, and following its removal, showed renewed receptivity in response to the introduction of a second male. Upon sexual satiation with the second male, females either received a novel third male or were reexposed to the original male. Total lordosis duration in the third bout in the group receiving a novel male was significantly greater than in the group reexposed to the original male. In Experiment 2, the insertion of a 1-h delay between the second and the third mating partner had no effect on the female's responsiveness, regardless of whether the third male was the original male or a novel male. In Experiment 3, removal of the ovaries followed by hormone replacement treatment (40 micrograms estradiol benzoate, 72 h prior to testing, and 500 micrograms progesterone, 4 h prior to testing) failed to alter the females' ability to discriminate between novel and familiar mating partners. These results demonstrate that females make clear discriminations among individual mating partners, that this can affect sexual receptivity and will continue to do so following a delay of at least 1 h, and that the effect is not mediated by the release of ovarian steroids.

Animals↗
PubMed1987

Intraventricular administration of l-kynurenine and kynuramine facilitates lordosis in the female rat.

Intraventricular administration of the tryptophan metabolites l-kynurenine (2-32 micrograms) and kynuramine (0.064-8 micrograms) facilitated lordosis behavior in estrogen-primed ovariectomized rats. The facilitatory effects of these drugs were not attenuated by pretreatment with the progesterone antagonist RU 38486, indicating that the effects were not mediated by release of adrenal progesterone. It is suggested that l-kynurenine and kynuramine may serve a physiological role in the modulation of female sexual behavior.

Animals↗
PubMed1987

Intermale social aggression in rats: suppression by medial hypothalamic lesions independently of enhanced defensiveness or decreased testicular testosterone.

Medial hypothalamic lesions or sham lesions were made in castrated adult male rats with subcutaneous implants of testosterone-filled silastic capsules. Seven days following surgery all animals were given a test of defensiveness (reactivity) toward an experimenter. The following day, groups composed of one lesioned male rat, one sham-lesioned male rat, and one intact female rat were placed in large cages. Beginning two weeks later, unfamiliar intruders were introduced into each colony on a weekly basis and the aggressive behavior of the residents recorded. All 12 of the sham-lesioned animals but only 2 of 12 lesioned animals displayed substantial intermale social aggression toward intruders. Analysis of individual elements of intermale social aggression indicated that the lesioned animals were deficient in attack, bite, and piloerection but not in on-top behavior. The deficit in intermale social aggression was not correlated with defensiveness toward the experimenter or body weight of the lesioned animals. It is argued that the medial hypothalamus plays a role in the modulation of intermale social aggression which is independent of its role in modulating defensiveness or testosterone production. These results also demonstrate that intermale social aggression develops even when testosterone levels are held relatively constant by replacing testicular testosterone with an artificial testosterone source.

Aggression↗
PubMed1987

An improved chamber for the observation and analysis of the sexual behavior of the female rat.

A new chamber designed to evaluate the sexual behavior of rats was found to have distinct advantages over chambers typically described in the literature. The new testing chamber is narrow, which maintains a male and female rat in the optimal orientation for the observer to view sexual behavior, i.e., in the side view. Moreover, the chamber consists of an upper and lower level, which allows the females an avenue of escape from the male. In Experiment 1 it was shown that use of the chamber increased the reliability of data gathered in evaluating the lordosis behavior of female rats. In Experiment 2 it was shown that the new chamber could be used to evaluate the pacing of copulation by female rats.

Animals↗
PubMed1987

Oxytocin-induced facilitation of lordosis behaviour in rats is progesterone-dependent.

Oxytocin was administered intracerebroventricularly to ovariectomized female rats and its effect on lordosis was examined. In Experiment 1a, oxytocin (0.17 mU in 4 microliters saline) failed to facilitate lordosis behaviour in animals primed acutely with 10 micrograms estradiol benzoate (EB) and 300 micrograms progesterone (P). In Experiment 1b, however, oxytocin significantly facilitated lordosis in animals primed acutely with 10 micrograms EB and 250 or 200 micrograms P. In Experiments 2a and 2b, oxytocin failed to facilitate lordosis in animals treated acutely with 10 micrograms EB, or chronically with 0.8 micrograms EB daily for eight days prior to testing. These results support the hypothesis that the facilitation of lordosis in ovariectomized rats by centrally-administered oxytocin is progesterone-dependent.

Animals↗
PubMed1987

Opioids and sexual behavior.

Opioids have long been known to inhibit sexual behavior. However, it is only within the last decade that the effects of opioids on sexual behavior have been studied extensively and a number of hormonal and neurochemical correlates established. In this review, the experimental literature on opioids and sexual behavior in humans and laboratory animals is examined. Clinical and anecdotal accounts of opioid use are also discussed, in addition to the pharmacology, neuroendocrinology, and biochemistry of opioid administration, to provide a synthesis of critical information. New research directions involving the study of endogenous opioid systems, opioid receptor subtypes, and the opioid modulation of neurotransmitter systems are outlined. Finally, a comprehensive bibliography of the human and animal literature is included.

Animals↗
PubMed1987

Neonatal testosterone propionate treatment in the female gerbil: morphological and behavioral effects.

The present experiment examined the effects of a single neonatal injection of 1 mg or 100 micrograms of testosterone propionate (TP) on the sexual behavior and morphology of the female Mongolian gerbil. Four groups were created: vehicle-treated males (VM), 1-mg TP-treated females (HTP), 100-micrograms TP-treated females (LTP), and vehicle-treated females (VF). In adulthood, tests of sexual behavior were carried out after gonadectomy and appropriate hormone replacement therapy. Results indicated that LTP, HTP, and VM animals were significantly less receptive than VF animals. In addition, VM animals displayed significantly more male sexual activity than HTP, LTP, or VF animals. Immediately after the final test for male sexual behavior, subjects were weighed, anogenital distances recorded, and scent glands measured (length and width). Results indicated that a significant degree of morphological masculinization had occurred in HTP subjects for all measures and for LTP subjects for scent gland width and anogenital distance. These findings suggest that in the gerbil, significant morphological masculinization and behavioral defeminization can both occur in teh absence of significant behavioral masculinization.

Animals↗
PubMed1986

Effects of 5-HT1A selective anxiolytics on lordosis behavior: interactions with progesterone.

Ipsapirone and gepirone, but not buspirone, facilitated lordosis in estrogen-treated rats, whereas all three drugs inhibited this behavior in rats treated with estrogen and progesterone. When administered at higher doses, ipsapirone, gepirone and buspirone inhibited lordosis in rats treated with either estrogen or estrogen and progesterone. These data are consistent with the proposal that 5-HT1A receptors mediate lordosis-inhibiting effects of 5-HT, and further suggest that some 5-HT1A agonists may facilitate lordosis by activity at autoreceptors. Finally, these data show that progesterone may modulate activity at 5-HT1A receptors.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1986

Serotonin type 2 antagonists inhibit lordosis behavior in the female rat: reversal with quipazine.

The theory that activation of serotonin type 2 (5-HT2) receptors facilitates lordosis behavior in the female rat was tested. The 5-HT2 antagonists pizotefin, cyproheptadine, metitepine, and ketanserin were found to inhibit lordosis behavior in ovariectomized rats that had been primed with estradiol benzoate and progesterone. Pipamperone was ineffective. The 5-HT2 agonist quipazine was ineffective alone, but it reversed the inhibitory effects of pizotefin, cyproheptadine, and ketanserin. It did not reverse the effects of metitepine. The results support the theory of a facilitatory role for 5-HT2 receptors in lordosis behavior.

Analysis of Variance↗
PubMed1986

Methysergide inhibits and facilitates lordosis behavior in the female rat in a time-dependent manner.

Reports in the literature have indicated a facilitatory effect of the serotonin antagonist methysergide on lordosis behavior, suggesting an inhibitory role for serotonergic activity. In the present series of experiments, methysergide (7 mg/kg) was found to inhibit lordosis behavior 30 min after intraperitoneal administration to females, treated chronically with estradiol benzoate, or acutely with estradiol benzoate and progesterone. However, methysergide was found to facilitate lordosis behavior 200 and 300 min after administration to female rats treated acutely with estradiol benzoate. These data suggest a time-dependent inhibitory effect of methysergide, and are consistent with the hypothesis that the activity of serotonin type 2 receptors facilitates lordosis behavior in the female rat.

Animals↗
PubMed1986

Intermale social aggression: suppression by medial preoptic area lesions.

The intermale social aggressive behavior of male rats cohabiting with a female rat was quantitatively scored weekly in response to the introduction of an unfamiliar intruding male. Resident male rats whose aggressiveness toward an intruder reached a criterion level were subjected to either sham lesions or bilateral lesions in the region of the medial preoptic area. The lesioned rats continued to exhibit levels of piloerection and lateral attack that were not significantly lower than those of sham-lesioned animals. However, the lesioned animals did emit significantly fewer bites and spent significantly less time in the "on-top" position than did sham-lesioned animals. The lesioned animals also displayed significantly less sexual behavior than the sham-lesioned animals but were not different in terms of defensiveness toward the experimenter. It is suggested that bilateral lesions in the region of the medial preoptic area cause a decrease in the intensity of intermale social aggression but do not prevent external stimuli from eliciting the aggression.

Aggression↗
PubMed1986

5-HT1A receptors: differential involvement in female and male sexual behavior in the rat.

The peripheral administration of the serotonin type 1A (5-HT1A) receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH DPAT) inhibited lordosis behavior in ovariectomized rats primed with estradiol benzoate. 8-OH DPAT was ineffective at 0.01 mg/kg, whereas inhibition occurred at the 0.03, 0.1, 0.3, 1, and 3 mg/kg doses. On the other hand, 8-OH DPAT enhanced various measures of male sexual behavior both in males and in females treated chronically with testosterone propionate. In males, 1 mg/kg 8-OH DPAT reduced ejaculation latencies and the number of intromissions prior to ejaculation. In females, 0.1 and 1 mg/kg 8-OH DPAT increased mount frequencies. These data indicate differential involvement of 5-HT1A receptors in male and female sexual behavior. In view of these and other recent data the authors conclude that activity at 5-HT2 receptors facilitates, whereas activity at 5-HT1 receptors may either facilitate or inhibit lordosis behavior. Furthermore, it is proposed that 5-HT1A receptors mediate inhibitory effects, whereas 5-HT1B receptors mediate presynaptic, facilitatory effects of serotonin.

8-Hydroxy-2-(di-n-propylamino)tetralin↗